Mobile devices can now connect to a wide variety of networks, including networks that use packet-switched connections for both data and voice. It is well-known that the mobility of these devices poses challenges for services that were previously designed for fixed telephones. For example, before the introduction of mobile devices, emergency service providers could depend on every telephone having a consistent location. When a customer dialed 911, the telephone company could route the call to the nearest emergency call center based on the known, fixed location of the customer's telephone. Similarly, the call center could use the telephone's known location to automatically determine a caller's location for sending emergency services. However, with mobile devices, call centers could no longer depend on the caller having a fixed location.
A second challenge for handling emergency calls from mobile devices is that when a mobile device makes an emergency call, the network cannot easily determine which emergency provider should receive the call. In general, a caller who dials 911 expects to be connected with a call center that is capable of dispatching emergency services to the caller's location. Dispatching was easy in traditional telephone networks, because every telephone was associated with one call center. However, historically, it has been complicated to ensure that calls from mobile devices are also correctly routed. Thus, there is a need for systems that can correctly route emergency calls from mobile devices.